


Overprotective Brother-in-law

by yuki_chicken



Series: Pregnant Magnus Prompts [15]
Category: Shadowhunters (TV)
Genre: Alec Lightwood Is Not Amused, M/M, Magnus Bane Is Amused, Mpreg, Mpreg Magnus Bane, Overprotective Jace Wayland, Pregnant Magnus Bane, Protective Jace Wayland, he thinks its cute, it does get annoying though
Language: English
Status: Completed
Published: 2019-07-10
Updated: 2019-07-10
Packaged: 2020-06-23 11:22:20
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 2,535
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19700350
Author URL: https://archiveofourown.org/users/yuki_chicken/pseuds/yuki_chicken
Summary: ((Basically the title))Jace is the first person to know about the pregnancy. He is the one to be extremely protective of his pregnant brother-in-law.Magnus is amused, Alec is not





	Overprotective Brother-in-law

**Author's Note:**

> basically, this is being dedicated to a crap ton (maybeeee 3???) of people for this story
> 
> 1\. @sasha1975 for being the sweetest person ever <3
> 
> 2.@sayangmagnus [on tumblr] for letting this post be found on my dash bless you
> 
> 3\. @fictional-worlds-are-exquisite [also on tumblr] for letting me turn a joke post into a new prompt idea....
> 
> {{even though i have a crap ton of other prompts to write}}

“Jace, can you tie my shoes for me?”

The blonde haired man turned to see his brother-in-law leaning against the wall with one foot in the air. The Warlock had stayed overnight in the Institute, due to a mission and the fact that they needed his help translating an ancient text. He raised an eyebrow in question, eyeing the Warlock up and down.

“Why would I tie your shoes?”

Magnus eyed his brother-in-law, smirking. Jace grew nervous with that smirk.

“It’s bad for the baby if I bend down like that”

Jace felt his jaw drop as he leaned down and placed Magnus’ foot on his knee.

“Man, Alec never tells me anything that little shit”

He waits for Magnus to place his foot down, grabbing for the other.

“Congratulations on the pregnancy, I guess”

Magnus grinned and patted Jace on the cheek, shuffling away from him. The blonde just blinked at him and turned to go find his parabatai to chew him out.

Suffice to say, everyone in the Institute found out about the pregnancy when they suddenly heard.

“MAGNUUUUUS!!!! WHAT THE FUCK?!?!?! WHY WOULD YOU TELL JACE THAT YOU’RE PREGNANT FIRST??”

Magnus, with Izzy and Clary, turned around from the center table as he heard the familiar pounding footsteps of his husband. The Shadowhunters were amused to see the Head, out of breath, face flushed, and leaning on the rails in exhaustion. The Warlock, ignoring the two gaping females, turned to face his husband.

“I asked him to tie my shoes for me, Alexander”

“But whyyyyyyy”

Seeing Alec whining, made everyone’s head spin. They watched with bated breath when Alec trudged down the stairs, to stand in front of Magnus. The Warlock looked up to his husband, whispering something. Alec made a sound as he went down to his knees in front of the Warlock’s stomach.

“I can’t wait to meet you, little one”

Everyone who knew Alexander Lightwood would think that he would be one to be extremely cautious over his husband’s delicate state.

It was the furthest thing from the truth.

The one to be overprotective of the pregnant Warlock was actually Jace Herondale. It shocked just about everyone. Cause, who knew the dumb, reckless blonde could be so overprotective. When confronted about it, Jace would scoff, curse, and leave the room. Only to return exactly five minutes later, to trail after Magnus like a lost puppy.

Magnus laughed and began calling him pup.

[[Alec choked and laughed so hard.]]

//

The first evidence was shown two weeks after the reveal of the pregnancy. Magnus had been trailing back and forth from the OPs center to the library to Izzy’s office. It was perfectly silent until Jace had walked in.

He saw Magnus pacing the center and his jaw had dropped. The Warlock was _still_ walking around? He eyed the Warlock and grabbed a nearby chair and placed it down next to a table.

“Magnus!!”

Everyone jumped and turned to stare at the blonde. The Warlock turned to look at his brother-in-law and raised a perfect eyebrow at him. The blonde only pointed to the chair and glared at the male. Magnus huffed and shuffled his way to the chair.

“You should be sitting down, you’ve been standing for too long. You know you’ve got another person in there right? Be more careful”

Magnus had rolled his eyes.

“Get me the next volume of this book then”

Jace saluted him in mock amusement and patted his belly before stalking over to the library. Magnus chuckled and shook his head, leaning on the table.

“Well, this certainly is going to be a very interesting nine months”

//

The second time Jace showed his brotherly instincts was about a week later.

Alec had gone to Alicante for some fancy meeting and didn’t want Magnus to be by himself. Magnus had protested and said that his wards were strong enough to protect him and he had his magic.

Alec had shot down that idea when he had reminded Magnus that he had passed out when he used a simple tracking spell the other day. He also brought up the fact that Catarina warned him to be cautious of his magic usage.

Magnus had grumbled under his breath as Alec smiled smugly at him and suggested he stay at the Institute with his siblings. Alec had then suggested that if Magnus complied then he would repay him with some good ass sex when he got back.

The pregnant Warlock had only groaned and pushed his ass back into his husband.

Alec was late to work by 2 hours.

The morning before Alec was due to return, the Lightwood siblings found Magnus in the cafeteria with his head down in his arms. The siblings and Clary had frowned. Jace had gone up next to the Warlock and grabbed his face. He stared at Magnus for a bit and noticed that he was paler than usual and the bags under his eyes were more prominent.

“Have you eaten anything yet? Can you keep it in? Has the morning sickness started? Can I get you anything?”

As if it was a trigger, as soon as Jace had mentioned morning sickness, the Warlock turned away from his brother and had gagged. The entire room stopped and eyed the Warlock. Jace saw the green tint in his face and cursed as he grabbed the nearby trashcan and placed it down in front of the Warlock. In the next second, the pregnant male heaved before throwing up whatever was left in his empty stomach. He coughed for a bit before leaning up, panting.

The poor Warlock looked up at his brother-in-law and whined. The blonde nodded and pushed Magnus’ chair back to pick him up in a bridal carry. The Warlock preened and placed his face into Jace’s neck. The blonde patted his back gently, picking up the trash can and leaving the dining hall.

He went to Alec’s room as quickly and gently as he could without jostling the male too much. Magnus whimpered as his body touched the bed and rolled over to cuddle Alec’s pillow. Jace brought the blanket up to his chest and cleaned out the can. He put it on the ground and patted the Warlock on the shoulder.

“I’ll go and make you some tea for your stomach and as much as it might suck. You should try to nibble on something so I’ll grab saltine crackers too”

Magnus made a noise and nodded his head. The blonde patted him once more, standing up to grab the things. Magnus watched him leave and smiled.

“He’s actually not so bad once you get to know him.”

He snuggled into the pillow and was soon fast asleep.

//

The third time anyone saw Jace’s ‘overprotective brother-in-law’ side was a couple of months later.

Magnus was currently 15 weeks pregnant and annoyed.

Do not get him wrong. He loved his in-laws, he really does.

He was currently walking through the Institute. He sighed as he heard the footsteps behind him. His brother-in-law was trailing behind him like a lost puppy. He stopped and sighed.

“Jace, you do know that even with the silencing rune, I can still hear you, right?”

He heard a noise and turned around to see Jace stomping his way towards right him. The blonde stopped in front of him and looked at him, crossing his arms.

“I’m just trying to look out for you. Alec is busy finalizing the details of the mission, something of which you shouldn’t be going on, and you are 15 weeks pregnant”

Magnus sighed and rubbed his temples.

“Jace…”

Jace stared at Magnus and was not about to change his mind.

“Ya know what…I’m going to Izzy”

Jace’s jaw dropped and watched as Magnus waddled away to find his sister-in-law.

~

An hour later, the Shadowhunters and some Downworlders gathered around the OPs Center. Jace looked around for his girlfriend and sister, something that should not be this hard.

He spotted clary’s bright red hair and made his way through the crowd to her and Izzy.

“Hey, you guys seen Magnus?”

Both girls looked at each other in confusion before turning back to Jace and shaking their heads.

“We thought that you were watching him?”

Jace paled a bit and cursed. He was about to bolt when Alec appeared.

“Alright, everyone listen up…”

Everyone stood in attention as Alec rambled off some details of the mission and what was required of everyone.

“Remember…no one dies tonight. We have each other’s back, no matter what”

“Yes, Sir!!!”

Alec nodded his head and dismissed everyone. He spotted his family and made his way over to them.

“Hey Jace, where’s Magnus?”

The blonde gulped nervously. How was he supposed to tell his brother and parabatai that he lost his pregnant husband? Jace opened his mouth to reply, but Alec had snickered. They stared in confusion and wondered if Alec had finally lost his mind. He turned and gestured for them to follow him. They followed obediently and soon they came to a stop in front of his room door.

“What?”

Alec stared before he opened the door, revealing the sleeping pregnant Warlock. Jace’s jaw dropped in surprise.

“Whaaaat?”

Alec patted him on the shoulder.

“Next time don’t irritate him so much”

//

The fourth time was a nerve-wracking day for everyone.

Magnus, at 32 weeks pregnant, wanted everyone to know that he was still an independent person. Yes, he waddled more than ever and had a giant globe in the front of him, but he’d be damned if people saw him as weak. He was still the most powerful Warlock in the country. He could take anything and anyone on.

So, this particular incident had ticked the Warlock to no end.

He was in the apothecary looking for an ingredient for a potion. He had magicked his tiny footstool in front of him. Using his magic, he spelled it so that it couldn’t tip over or he couldn’t fall from it.

He was two inches from the vial he needed when he heard the door slam open and a screech. He turned and saw Jace and Alec with a ticked off look on their faces. He was about to explain when they both charged over to him. Alec had grabbed him and Jace had taken the stool away.

Alec had carried him out of the apothecary and into the living room. Clary and Izzy followed behind nervously. Their gazes were going between the Warlock and two Shadowhunters. Magnus opened his mouth to say something when Jace beat him to it.

“By the angel!!!! MAGNUS!!! What the hell were you thinking??!?!”

Magnus’ mouth dropped open in shock.

“You weren’t thinking that’s what!!! You could’ve injured yourself or the baby and then what??”

Alec silently fumed next to him. His eyes shone in disappointment at him. Magnus felt the tears gather in his eyes.

‘Damn hormones’

“Well?? Do you have anything to say for yourself?”

The Warlock flinched.

He hated it when people were mad at him. Rationally, he knew that he was supposed to talk to them, but he couldn’t. Not right now. So, he did the next best thing he could think of. He lifted his hand and the next thing the Shadowhunters knew, they were in a heap on the floor of the OPs Center.

They all stared at each other in shock before a pissed off look overcame the two males. Izzy and Clary thought quickly and sprawled themselves over the boys. They gasped as they stared at their sister and girlfriend.

“You two need to calm down”

Izzy stated as she glared at the two. They went too far and she should’ve stopped them earlier.

“You both scared Magnus!! You know pregnancy hormones are hell on a person and you both being mad and yelling at him didn’t help. Plus, Magnus is a Warlock I’m sure he spelled the entire apartment to help him if something had happened”

The two gaped at Clary before they both deflated in defeat. They winced when they thought back on their words and actions. Magnus must’ve gotten scared. Alec sighed and ran his hand through his hair. He should’ve known better, there were some days where Magnus still felt insecure and stuff. He shouldn’t have gotten so mad at his husband. Clary was right, with the addition of the pregnancy, his emotions were all over the place.

He looked over at Clary and asked her to open a portal back to the loft. She agreed.

Sometime later, while still mulling over his guilt, Jace felt the happiness radiating from his parabatai bond. He sighed. At least Alec had the balls to apologize so quickly. The blonde continued to mull in silence, not knowing that Clary and Izzy were plotting.

The Warlock had shown up later in the evening, placing a hand on the hem of Jace’s jacket as he looked down.

Jace beamed and brought the Warlock into a hug. Everyone sighed in relief.

//

The fifth time was when the Clave decided to be assholes on the wrong damn day.

Magnus had woken up that morning extremely cranky. Alec had been gone for two days and wasn’t due home for another two. Magnus was once again in the Institute.

He woke up to his entire body on fire and crampy. He made to stand up but quickly sat down again with a hiss. He felt a tugging sensation and a gush and looked down to his a liquid staining his pants.

His eyes widened and he quickly sent a message to Izzy and Catarina. He groaned and hunched over, leaning an arm on the bedside table. He looked up when the door burst open, revealing Cat, Clary, Jace, and Izzy.

Jace had a seraph blade in hand and Magnus had just stared.

“Really, Jace?”

Jace blinked and stared at Izzy and then pointed at Magnus.

“I never said that he was being attacked stupid”

Jace sighed and sheathed his blade and turned to Magnus when the Warlock let out a hiss. He took his stele out and activated his strength rune and moved to the Warlock and picked him up. Magnus tried to protest but whimpered in pain. The blonde quickly made his way out and to the Infirmary. He stopped Underhill on the way and told him to contact Alec.

They made their way to the infirmary and sat with Magnus and coaching him through the pain.

About thirty minutes after Cat kicked them out, an out of breath Alec appeared. He tripped over his own feet and looked up at his siblings. Their jaws dropped and Jace quickly grabbed Alec’s arm to hoist him up.

“Hurry up and get in there bro, you’re about to be a dad”

Alec nodded dumbly and went through the doors. They were greeted briefly by Magnus’ screams and whimpers (and actively cursing Alec). The Archer gulped nervously before bracing himself and going in.

Jace beamed as he looked down at the tiny girl in his brother-in-law’s arms. She was the exact replica of Alec but with Magnus’ Warlock mark.

He loved his niece.

His niece Irina Marissa Lightwood.

**Author's Note:**

> I found the damn Tumblr post at freaking 1 am and it's been scratching at me for like ever [meaning the past 4 hours and shit]
> 
> [from the other day]
> 
> y'all know what to do!!!! prompt requests are on the original post and comment/kudos if you guys liked this


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